/*
 *    Copyright 2006-2020 the original author or authors.
 *
 *    Licensed under the Apache License, Version 2.0 (the "License");
 *    you may not use this file except in compliance with the License.
 *    You may obtain a copy of the License at
 *
 *       http://www.apache.org/licenses/LICENSE-2.0
 *
 *    Unless required by applicable law or agreed to in writing, software
 *    distributed under the License is distributed on an "AS IS" BASIS,
 *    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *    See the License for the specific language governing permissions and
 *    limitations under the License.
 */
package org.mybatis.generator.api.dom.kotlin.render;

import java.util.ArrayList;
import java.util.List;
import java.util.stream.Collectors;

import org.mybatis.generator.api.dom.kotlin.KotlinFunction;

public class KotlinFunctionRenderer {
	public List<String> render(KotlinFunction function) {

		List<String> answer = new ArrayList<>(function.getAnnotations());

		answer.add(renderFirstLine(function));

		answer.addAll(function.getCodeLines().stream().map(KotlinRenderingUtilities::kotlinIndent)
				.collect(Collectors.toList()));

		if (!function.getCodeLines().isEmpty() && !function.isOneLineFunction()) {
			answer.add("}"); //$NON-NLS-1$
		}

		return answer;
	}

	private String renderFirstLine(KotlinFunction function) {
		String firstLine = KotlinRenderingUtilities.renderModifiers(function.getModifiers()) + "fun " //$NON-NLS-1$
				+ function.getName() + "("; //$NON-NLS-1$

		firstLine += renderArguments(function);
		firstLine += ")"; //$NON-NLS-1$
		firstLine += renderReturnType(function);

		if (!function.getCodeLines().isEmpty()) {
			if (function.isOneLineFunction()) {
				firstLine += " ="; //$NON-NLS-1$
			} else {
				firstLine += " {"; //$NON-NLS-1$
			}
		}

		return firstLine;
	}

	private String renderArguments(KotlinFunction function) {
		KotlinArgRenderer argRenderer = new KotlinArgRenderer();

		return function.getArguments().stream().map(argRenderer::render).collect(Collectors.joining(", ")); //$NON-NLS-1$
	}

	private String renderReturnType(KotlinFunction function) {
		return function.getExplicitReturnType().map(s -> ": " + s) //$NON-NLS-1$
				.orElse(""); //$NON-NLS-1$
	}
}
